This invention relates to a fuel supply and fuel return system for an internal combustion engine and more particularly to an integral and co-axial supply and return line system.
In a fuel system for an internal combustion engine, it is desirable to have a fuel return line that will return excess fuel or fuel vapors to the storage tank so as to prevent vaporlock conditions within the internal combustion engine.
In the automotive industry, separate lines are used for fuel supply and fuel return. However, in the marine industry, separate return fuel lines are generally unacceptable due to the fact that any failure or leak of the return fuel line will cause fuel to be pumped or leaked into the compartments surrounding the return line e.g., bilge, engine compartment, etc. Since the operation of the engine is not interrupted by such a leak, a leak of this type may be undetected for a considerable amount of time and may thus lead to unsafe conditions on the boat.
The present invention provides a fuel return line that is integral with, co-axial with and contained within the fuel supply line so that any leak in the return line is contained by the fuel supply line.
In accordance with another aspect of the invention, the end of the return line communicating with the fuel tank is disposed above the level of the fuel in the fuel tank and the pressure in the return line is greater than that in the supply line so that a rupture in the return line cause air from the fuel tank to be introduced into the supply line which causes the engine to cease operating.